Sweeps are devices for removal of agricultural products (e.g., grain) from the floor of a silo or other storage bin. Typically, a sweep has a length which stretches across the bin floor, with the length bearing an auger, a paddle-bearing conveyor, or other means for moving product on the bin floor, such that as the sweep's length is pushed across the floor, the means for moving product “sweeps” the product across the bin floor to one end of the sweep's length (typically an “inner” end of the sweep, at which a sump is provided to receive the product). For useful background regarding sweeps, the reader is referred to U.S. Pat. No. 6,017,180 to Wilham and U.S. Pat. No. 7,544,031 to Kaeb et al., as well as to the patents referenced elsewhere in this document.
It is recognized that sweeps have optimal performance on smooth, flat bin floors. However, particularly in larger bins, flat floors are harder to achieve. Differences in height tend to arise owing to difficulties with fully leveling concrete poured to form the floor, and owing to the ground settling or otherwise shifting beneath the bin floor. To compensate for height irregularities, sweeps are typically constructed to vertically pivot along their lengths, or to at least vertically pivot at their inner ends, so that the length of the sweep (or subsections thereof) can independently raise and lower to better follow the contour of the bin floor as they orbit the floor. As examples, U.S. Pat. No. 6,499,930 to Dixon describes a sweep having an inner pivot, allowing the entirety of the length of the sweep to pivot upwardly and downwardly to follow the height of the grain beneath, and U.S. Pat. No. 8,770,388 to Chaon et al. and U.S. Pat. No. 8,967,937 to Schuelke et al. describe sweeps having sweep sections arrayed along their lengths wherein certain sweep sections are pivotally connected to each other such that one sweep section may vertically pivot in relation to its adjacent sweep section.
In the foregoing pivoting sweeps, the pivots tend to be constructed by simply rotationally pinning sweep sections to each other, and/or to the central bearing about which the length of the sweep rotates. These simple pinned pivots allow some degree of variability in the heights of adjacent sweep sections, but may not allow the sweep and/or its sections to precisely match floor contours. Additionally, these simple pinned pivots can sometimes bind as the sweep is driven about the bin floor, with the adjacent pinned sweep sections being driven forwardly into the grain.